1. Field of the Invention
This invention relates to a lamination type heat exchanger suitable for an evaporator of an automotive air conditioner and including a lamination structure of metallic plates for forming fluid passages, and a pipe joint that is disposed at an end of the lamination structure in a lamination direction for providing fluid outlet and inlet portions.
2. Description of the Related Art
Recently, a refrigerant evaporator for an automotive air conditioner has been required to include a pipe joint that is disposed at a side central portion of a heat exchanging part for a refrigerant pipe arrangement. This pipe arrangement has high flexibility, because a pipe can be directly taken out from the side of the heat exchanging part, and the position where the pipe is taken out can be arbitrarily selected within the side region of the heat exchanging part.
The applicant of the present invention proposed a lamination type evaporator in a preceding pending Japanese Patent Application No. 9-257095. In the evaporator, an inlet tank portion for distributing refrigerant into refrigerant passages in a heat exchanging part is positioned at an end in refrigerant flow direction of the heat exchanging part, and an outlet tank portion for receiving the refrigerant that passes through the heat exchanging part is positioned at the other end in the refrigerant flow direction of the heat exchanging part. A side refrigerant inlet passage for conducting refrigerant into the inlet tank portion and a side refrigerant outlet passage into which refrigerant flows from the outlet tank portion are provided at a side of the heat exchanging part (at an end in a lamination direction of metallic thin plates).
The side refrigerant inlet passage is connected to a refrigerant inlet portion of a pipe joint, while the side refrigerant outlet passage is connected to a refrigerant outlet portion of the pipe joint. Specifically, the side refrigerant inlet passage and the side refrigerant outlet passage are defined by an end plate and a side plate that are positioned at the side of the heat exchanging part (at the end in the lamination direction of the metallic thin plates). The pipe joint is joined to the side plate. In the preceding application, however, when an external refrigerant pipe is connected to the pipe joint, force is externally applied to the joining (brazing) portion between the pipe joint and the side plate, thereby generating excessive stress in the joining portion. This excessive stress can decreases strength of the joining portion.